One thing you may have noticed in the previous chapters is that commands with too much text output appear to get cut off. You can see the tail end, but the rest seems to go above the window. If you try scrolling up, it will not work. What is going on here?

The start of a command is not lost forever. It still exists; it has simply scrolled off the screen.

In order to work its magic and keep everything in a single terminal window, tmux has to hide all of the text that won't fit in the currently viewed pane. It keeps all of this text stored in something called Window history.

Think of it like pages in a physical book. A book contains far more text than you can see at any given point in time, but to make it manageable, all of that text is on pages that aren't visible at the same time. The one page that is visible is the one you have opened.

Similarly, tmux maintains all of the text that didn't fit on the pane you are currently viewing and tucks it away in the Window...